Hydraulic lift



April 30, 1935. v E. F. RIES 1;999,848

HYDRAULI G LIFT Filed Nov. 11, 1932 3'Sheets-Sheet l INVENTOR nayATTORNEYS I E. F. RIES HYDRAULIC LIFT April 30, 1935.

Filed Nov. 11, 1932 3 Sheets-Sheet 2 INVENTOR ATTORNEYS April 30, 1935.

E. F. RIES 1,999,848

HYDRAULIC LIFT 3 Sheets-Sheet 3 Filed NOV. 11, 1932- ATTO RN EYSPatented Apr. 30, 1935 uNirso TATES HYDRAULIC LIFT Elmer F. Ries,Bridgetown, Ohio, ssigns! to The Max Wocher & Son Company, Cincinnati,Ohio, a corporation of Ohio Application November 11, 1932, Serial No.642,278

3 Claims.

This invention relates to hydraulic lifts, of the type adapted for usein doctors or dentists chairs, operating tables etc., adapted to beraised and lowered to dispose the patient at a height or levelconvenient to perform the professional services. Obviously this class offurniture also includes chairs suitable for use in barber shops, beautyparlors and other establishments of this sort.

This invention comes into being not because of the inadequacy ofprevious apparatus from the point of view of getting the patient orcustomer up or down, but is responsive to the thought that it isdesirable to raise or lower the patient with the least possible physicalsensation to the patient.

The object of the invention is, therefore, to provide compact and highlyemcient mechanism for raising and lowering the patient supportingportion of a piece of professional furniture, the raising and loweringto be facilly performed by the administrator of the treatment with theleast possible sensation to the occupant of the article of furniture.

fully apparent from a description of the aceom panying drawings, inwhich:

Figure 1 is a perspective view of a chair incorporating the presentimprovements.

Figure 2 is a fragmentary view, certain parts of the view being shown insection and shifted for the purpose of illustrating the position of thetreadle and apparatus to permit descent of the chair.

Figure 3 is a fragmentary sectional view illustrating the connectionfrom the treadle to the pumping pistons and showing the chair locked ina particular position 'of elevation.

Figure 4 is a top plan view of the base or pedestal of the chair, withthe chair mounting block removed.

- Figure 5 is a sectional view taken on line 5-5, Figure 4, illustratingthe mounting and arrangement of the hydraulically operated pistons andtheir cylinders. I

Figure 6 is a fragmentary side view of the top portion of the pedestalillustrating the treadle and general mounting of the rotatable chairsupport.

Figure l is a sectional view taken on line 1-1, Figure 4, detailing thestructure of the hydraulic double piston pump and showing the liftpistons at the highest positions with the by-pass functioning.

- Figure 8 is an enlarged central sectional view Further objects andadvantages will be more of one of the valves at the base of a pumppiston. y

Figure '9 is a top plan view of the valve shown in Figure 8. v

Figure lGis a view taken similar to Figure 8, 5 showing the valve inopenposition. r V

Fifure ii is a sectional view taken on line ii-i E, Figure 8,detailingthe construction of the lower valve element. 7 H v i V Figure12is a general view of the pedestal and revolving support for the chair, aportion of the view being shown in section for further illustrating thepump, and the treadle lever-being shown in various positions ofoperation the full line position indicating position for maintaining thechair in fixed elevated position. I

The concept underlying this invention is that it is desirable to elevatethe portion of the chair supporting the patient by means of ahydrauliclift device which provides a substantiallyuniform and even liftingmotion. From the point of View of the doctor or person administering thetreatment, the foot treadle is not'only the conventional instrument usedfor manipulating the chair, but is the most convenient. The invention,therefore, specifically resides in the particular type of elevatingdevice adapted to be operated by a foot treadle without undue exertionon the part of the operator and adapted to lift the weight of a persongently and uni-7 formly, reducing to a minimum the physical sensation ofbeing lifted.

The invention comprises a two cylinder hydraulic pump adapted .tooperate plunger mechanism attached to the support for the patient, onepiston of the pump being operated by the down stroke of the foottreadle, the other cylinder of the pump being operated by a spring, thepower for-which'is stored in the spring by said downward stroke ofthefoottreadle. In other words, 40 the downward stroke of the foottreadle'both operates one cylinder of the pump for-lifting the patientand compressesthe spring whichin turnv executes the upward stroke of thefoot treadle and at the same time executes the effective lifting strokeof the other cylinder of the pump;

Therefore, as the operator moves the foot treadle up and down with hisfoot, the patient is elevated substantially uniformly, evenly andcontinuously. The thought antecedent to-this invention is unusual inthat it has vnot been recognized in the past that the ordinary downwardstroke of thefoot'treadle under the weight, of the operator hadsufficient power inherent in it both to elevatev thepatient.directlyaand to,

includes a cylindrical portion -22 depending into V hydraulic lift unit.

store sufficient power in a spring to continue the elevation during thereverse or return stroke of the foot treadle.

Referring specifically to the drawing, the invention as disclosedconsists primarily of a patient support in the form of a chair i5mounted for rotation and elevation on a pedestal I6, in which pedestalthe elevating mechanism is housed. The structure of the chair is notdescribed in detail inasmuch as the presentinvention is directedentirely to the mounting and lift for this part of n the apparatusrather than to the structure of the chair.

The chair is directly mounted on two hydraulically operated pistons11,11 by means of an attachment block or plate l8 attached to the upperends of the pistons by means of screws l9. These pistons extend into thepedestal l6 and are operatively mounted in cylinders 29 as a part of thegeneral elevating unit rotatively mounted on the, pedestal or base it.The main element or body 2! of the hydraulic lift or elevating mechanismthe hollow base i6 and a horizontal supporting flange 23 which includesa downwardly extended lip or flange portion 24 engaged about a circularbearing block 25 fixed to the upper end of the pedestal by screws 26.

A circular arrangement of ball bearings 2? is provided operating in acircular recess 28 in the top of the bearing block 25 and directlysupporting the hydraulic lift unit. The lift unit is held in assembly onthe bearing block by means of screws 29 disposed laterally through thedepending lip or flange 24 and engaged in an annular groove 38 in thebearing block 25. One of these screws has'a hand bar 3| at its outer endfor hand operation for tightening the set screw into the groove andsetting the rotatable chair carrying lift unit in fixed position againstrotation.

- Suitable oil wiper washers 32 are provided at the upper ends of thecylinders in which the elevating pistons are mounted for preventing oilleakage by way of the cylinder bore. The upper ends of the cylinders areflared for receiving the oil wiped from the pistons, this oil drainingback to the reservoir by way of longitudinally disposed grooves 32extending to a by-pass slot hereinafter described and communicating withthe reservoir.

The lower ends of the cylindersin which the plungers or pistons aremounted are closed by means of plugs 33 and oil is fed to the lower endsof the hydraulic cylinders by means of ports 34 which lead from thecylinders of the pump.

The pump is operated by means of a foot treadle 35. This foot treadle ispivoted at its inner end on a depending pivot bracket 36 which is fixedto the depending flange or lip of the rotatable The hydraulic pump isduplex including two pistons 37, 3? which operate alternately forforcing the oil into the lower ends of the elevating cylinders. For thispurpose a walkingbeam 38 is fulcrumed on pivot lugs 39 of the mainelement 2| of the hydraulic unit and has its respective outer endsconnected to the upper ends of the respective pistons 37, 31 of theduplex pump by piston rods 40, 49. The pivotal axis of this fulcrumedlever crosses the axis of the elevating pistons and for that reason thelever is formed with pivotal side extensions 4! extending from one endof the lever and curved around the pistons, for pivo'tal'at-tachment onthe pivot lugs previously'mentioned; f I

to these levers is flexible.

Set screws 42 are provided in the lever 38 and are adapted to engage theelevating hydraulic pistons H, i! when the foot treadle is in upperpositionor in that position in which the chair will be sustained againstdescent. The action of these screws in sustaining and maintaining thechair in elevated position will be described later in conjunction withcertain other coordinated devices.

The treadle lever 35 is connected to the outer end of a fulcrumedoperating lever 43 for operating the walking beam 38 by means of a rod44 extended to an intermediate pivot 45 on the treadle. The inner end ofthe operating lever #3 is pivotally connected to the pivot 45 betweenthe walking beam and one of the piston rods of the pump. In view of thefact that the pistons and rods of the pump are mounted against lateraldisplacement from a definite axial position of reciprocation, and sincethe ends of the beam move on an are relative to the pivot connections tothe piston rods, the walking beam connection To this end the ends of thewalking beam are' slotted as at 41 and the pivot pins inserted throughthe upper ends of the piston rods of the beam lie in these slots. Thesame type of connection is used for the operating lever, the end of thislever being slotted in the same manner as at 48. I

As stated before, the hydraulic pump includes two pistons 37, 37. One ofthese pistons is moved downwardly by downward movement of the foottreadle and upwardly by the expansive action of a coil spring 59 whenfoot pressure is relieved on the treadle. The reservoir is between thecylinders which are connected by a slot 59 extended between theelevating pistons. The reservoir thus formed and as contained above thepistons supplies the'oil to the lift through valves in the pistonsoperated by movement of the pistons in the respective directions.

The pistons 37, 31 are disposed in cylinder bores 5| formed at the lowerend of the hydraulic unit and the piston rods 4!) are disposed throughguides 52 screwed into the upper end of the ends of thecylinders. Thespring 49 of the one piston is disposed under compression between theparticular guide 52 and a nut 53 on the rod located just above thepiston, thereby constantly exerting a downward force on the piston.

Two valves are provided for each piston, the structure of the piston andits valves being identical for the respective pistons. One of thevalves, namely 54, is mounted at the lower end of the cylinder and isurged upwardly against a seat 55 formed by a shoulder in the bore. Thevalve is urged by means of a compression spring 5% disposed between thevalve; about a guide stud 51 thereof, and. a closure plug 58 at theextreme lower end of the cylinder.

The other valve contained in each piston is mounted and formed in thefollowing manner: The piston is sectional. One part namely 59 is rigidlyfixed on the lower end of the piston rod to and includes a main flangeBil including a circular series of ports 5| and forming part of thepiston and an axially disposed depending stud 62 for supporting therelatively movable piston part or valve 63. This stud 62 includes a head64 cooperating with a shoulder 65 formed by a counterbore in the valveelement hung thereon. The valve or piston element includes a series ofports 56 circularly arranged on a radius less than that of the radiusdefining the circular arrang ment; of ports in the flange of the upperpiston section59.

- As shown in; Figure-.10, when the piston-moves upwardly,=the lowerormovable valve section 63 moves down to rest on the head, .64? of a. stud62 leaving a space between the elements whereby the oil will ,flowidownwardly through the upper ports 61 between the plates and downwardlythrough the ports 66 in the lower element. A circular groove 6? isprovided in the top or abutting surface of the lower or valve element 63on the same radius as the arrangement of ports in the upper element,whereby the oil at all times can enter this groove and pass out thesides of the piston through lubricating passageways 68 extendingradially for lubricating the walls ofthe cylinder and the piston toinsure efiicient operation of the pistons and working of the valves.

It will be apparent that as a particular piston moves downwardly itscontained valve structure will be closed by back pressure against thelower piston or valve section 63, whereas the. lower valve 54 in thecylinder will open, the piston then forcing oil past the lower valve andinto the lower ends of the elevating cylinders by way of the passageway34 extending toboth cylinders.

' of the lift; At this time the other piston moves upwardly for openingits contained valve permitting oil to flow between the piston and thecoordinating valve 54 which is closed at the time.

The outer piston is moved downwardly byfoot pressure, at which time thespring 49 operating.

the other piston is compressed by upward movement of the piston and apiston operatingpressure or force built up for operating this pistonwhen the operator relieves pressure on the treadle;

This, as stated before, insures a smooth continuous pumping of oilto theelevating cylinders for raising the chair without perceptible jerk.

For the purpose of connecting thelower ends of the pump cylinders to thelower ends of the hydraulic'lift cylinders, these respective cylindersof each deviceare connected by intersecting cross passageways $9, 10. 7

As shown in Figure 12, there are three positions of importance for thetreadle. When the treadle is fully elevated such as will occur when theoper ator takes his foot off the treadle due to the action of the heavyspring 49 under compression acting on one of the pistons, the walkingbeam is swung and engages or wedges the stop-screws 42' thereof againstthe elevating plungers at an angle. This action either independently orin conjunction with the closed position of both of the'control valves. 5preventing the return of oil from the lift cylinders to the reservoir,locks and maintains the chair in established elevated posidownwardlymoved outer piston 55 contacts the flow control valve 56 as shown inFigure 2 through the medium of the depending stud 52 as shown in Figure2. This permits the flowof oil from the lower ends of. the elevatingcylinders back into the pump atagrateyof flow resulting in a slowcomfortable-des'centof the 'chair.v In order to-limit the elevation'ofthe chair and'elevatingpist'ons, a crossgroove- 73 is proend of eachlift cylinder 20 resting on the closure plug 33 thereof. These springslie normally expanded in the cylinders and are contacted and. compressedby the pistons as they reach lowest position. When the stop springs arecompressed an amount in proportion to the weight on the liftingpistonsthey serve as, full andpositive steps. Yieldable limiting meansare thus provided preventing any jar or abrupt stop as the chair comesdown to its limit.

By the present arrangement, the double piston I pump, operated bycombined foot pressure and spring pressure, and the elevating pistonsand cylindersare all contained in'the cylindrical elemerit or casingforming the main or body portion 22 of the hydraulic device. Theelevation of the chair is uniform and steady with a total eliminationofthe jerks or interruptions to upward travel as would be caused byinterruption in the pumpingof oil to the hydraulic pistons.

The spring compels the completion 'of a given cycle of operation.

Havingdescribed the invention, I desire to be plane oftheir axesdisposed at right angles tothe. common plane of the axes of thehydraulically operated pistons, leverage means for alternately operatingsaid'pumping pistons, said rotatably-so mounted body including apassageway from the pumping cylinders to the hydraulic lifting pistoncylinders, and valves for controlling the flow of fluid underthe actionof the pump.

, 2. In a hydraulic lift for professional furniture, a pedestal, acylinder element mounted for rotation on said pedestal, a lifting pistonmounted for verticalreciprocation in a cylinder of said cylinderelement, a piston pump mountedin said cylinder element and adapted topump fiuidto the base of said lifting. piston, a fulcrumed pump pistonoperating lever, means for operating said pump operating lever, and anelement mounted in said pump operating lever and disposed for engagementwith the elevating piston when the pump operating lever is in apredetermined position, said element exerting a lateral wedging actionon the elevating pistonfor locking the same in position of elevation. I

3. In a hydraulic lift for professional funiture, a base element, acylinder element mounted on.

said base, a hydraulic lift piston mounted for reciprocation in saidcylinder element, a double piston pump for pumping fluid to the base ofsaid lifting piston, a fulcrumed lever mounted Jim.

i 5 pump piston, spring means compressed bysaid efiective'movement ofsaid first piston and opera tive to move the other piston for effectivestroke,

:said fulcrurned lever adapted to engage the elevate ing piston at anangle, said engagement induced by the spring action on eflfective strokeof the spring urged piston for wedging the elevating piston in itsguidea'nd lockingthe same in position of elevation. I t r V ELMER F.RIES.

